hotfix: error on deleting assistant (#8190)

fix: error on deleting assistant

src/renderer/src/hooks/useTopic.ts

@@ -34,7 +34,7 @@ export function useActiveTopic(assistantId: string, topic?: Topic) {
 
   useEffect(() => {
     // activeTopic not in assistant.topics
-    if (assistant && !find(assistant.topics, { id: activeTopic?.id })) {
+    if (assistant && assistant.topics.length > 0 && !find(assistant.topics, { id: activeTopic?.id })) {
       setActiveTopic(assistant.topics[0])
     }
   }, [activeTopic?.id, assistant])

src/renderer/src/pages/home/HomePage.tsx

@@ -29,6 +29,7 @@ const HomePage: FC = () => {
 
   const setActiveAssistant = useCallback(
     (newAssistant: Assistant) => {
+      if (newAssistant.id === activeAssistant.id) return
       startTransition(() => {
         _setActiveAssistant(newAssistant)
         // 同步更新 active topic，避免不必要的重新渲染
@@ -36,7 +37,7 @@ const HomePage: FC = () => {
         _setActiveTopic((prev) => (newTopic?.id === prev.id ? prev : newTopic))
       })
     },
-    [_setActiveTopic]
+    [_setActiveTopic, activeAssistant]
   )
 
   const setActiveTopic = useCallback(